Many people know about Warren Buffett, but not enough people know about his right-hand man, Charlie Munger. See here for Munger's 1994 lesson on "Elementary, Worldly Wisdom As It Relates To Investment Management and Business":
"If people tell you what you really don't want to hear, that's unpleasant--there's an almost automatic reaction of antipathy. You have to train yourself out of it. It isn't foredestined that you have to be this way. But you will tend to be this way if you don't think about it."
"I think the reason we get into such idiocy in investment management is best illustrated by a story that I tell about the guy who sold fishing tackle. I asked him, 'My God, they're purple and green. Do fish really take these lures?' And he said, 'Mister, I don't sell to fish.'"
Also, see here for more "Mungerisms" and my brief meeting with Mr. Munger.